Process for dyeing and figuring woven, knitted and plaited fabrics, leather, and other materials



Patented Sept. 6, 1932 UNITED STATES WALTER HAENDEL, or BERLIN,GEnM'AivY rEooEss FOR nYEme AND FIGURING wovEn, KNITTED AND PLAITEDFABRICS, LEATHER, AND OTHER MATERIALS No Drawing. Application filedMarch 28, 1929, Serial No. 350,820, and in Germany April 7, 1928;

The present invention relates to a photochemical process for dyeing andfiguring supports of any kind, in which light-sensitive bodies areapplied to the support and then the latter is subjected to the action oflight. 5. The essence of the invention consists in this that, moreparticularly for producing coloured patterns on dark ground .twocompounds are applied to the support, one of which forms dyes only onexposure to light, whilst the other on the contrary, is capable ofproducing the dye only in the dark.

The advantage of the new process consists in this, that two differentcolours can be produced in one operative process by a singleillumination. For formin one colour alightsensitive sulphonated bod issuitable. For the other colour, which orms in the dark, other dyestuffsare available,'for instance the indigo investigated by F. Sachs, andproduced by Baeyers synthesis from nitrobenzalda. hydeand acetone. As"is well known nitrobenzaldehyde when exposed to light is converted intonitrosobenzoic acid:

ono COOH llght N02. NO.

An intermediate product in the above synthesis is a phenyl-lactio acidketone with the reactive nitro group. This nitro-ketone, when acted onby fixed alkali, forms indigo, while under the a'ctionof light it isdestroyed in the same way as described above and loses this capacity. IA

For 6. eing and figuring materials by the process escribed above, thefollowing method is adopted. The material is treated with thesulphonic'di'azo compound and nitrophenyL,

lactic ketone. The support is now exp sed to light in a single operativeprocess, thos places which are not to be influenced by the light beingcovered'ov'er by means of a stencil or an imprint. This im'printconslsts of a light absorbin'g covering colourwhich does not dye thefabric. At the exposed places the azo dyestufi' will thenbe formed,while at the nonexposed places, indigo will be formed under the 'actionof phenol-alkali.

5o It is also possible to combinethe processes usually employed inprinting with dyestuffswith the new process described above. Thus, -forinstance, the cover negative printing process may be carried out in sucha manner that the dye ground of the material is "formed photochemically,that is that the material is first treated with the light-sensitivecolourless dyestuif components (for instance'with sodiumphenyhdiazo-sulphonate and phenol alkali), the pattern is then printedon in the usual way, that is-with, the finished dyestuif and the usualadditions,and thee whole is then exposed. The printed on pattern acts inthis case as a light-protective colour, that is partially protects thelight-sensitive dyestufi components which produce the coloured groundfrom being exposed and at the same time forms the colour of the pattern.

The light-sensi ive compounds may for in stance be produced as follows:

1. Sodium phenol-diazmsulphonate for the yellow partial impression. 9.3grms. of ani- K line are dissolved in hydrochloric acid having a HClcontent of 10 grms. are cooled to 3 to 5 C. and are quickly mixed with7.2 grms. sodium nitritedissolved in a little water. During thisoperation care should be taken that the temperature does not rise above5 C. Phenyl-diazochloride is formed, which may be readily converted intothe sulphonicsalt by being mixed with sodium sulphite. For this purposesodium bisulphite and sodium hydroxide are .used with advantage. As thisrecipe is carried out 'for mol., the two latter reagents are of coursealso used in this quantity, that is 10.4 rms. bisulphite and 4 grms.sodium hydroxi e.

For treating the material a mixture of s odium phenyl-diazosulphonate,'phenol and sodium hydroxide are used in molecularv quantities. 2. Sodiumdiphenyltetrazosulphonate for the red; partial' impression. .ommen.cingwith benzidine the process is carried'out with double molecularquantities in the manner 'de-' r scribed in paragraph 1. For exposure amixture of this compound with resorzin and sodium hydroxide inmolecular'quantities is used. F

'3. Sodium ditollyltetrazosulphonate for 99 the blue partial impression.Commencing with tolidine, the process'is carried out as withbenzidine-by coupling forv the exposure with 1.8 amidonaphthol-QAdisulphonic acid and ,8 naphtylamine each in half molecular quantities.The tone and the fastness of j the colours may be subsequentlyinfluenced by treating with metallic salts, such as cupric chloride,ferric chloride, and potassium bichromate.

In the manner described every -N=N compound may be converted into asulpho: nated compound and developed on the material into a dyestuff bythe photo-chemical process above described. ,It is also possible furtherto diazotize either before or after sulphonation a tetrazo, salt coupledhalf molecularly with an amine and thus to build up complex molecules.The sulphonated N=N- salts are without exceptionconsiderably more stablethan the hydrochlorides, most of them even to an unlimited extent andmay therefore be made for stock.

WhatI claim is:

- 1. A process for producing a coloured pattern on a dark ground onwoven, knitted and plaited fabrics, leather and other materials,consisting in treating the material with two compounds, one of which iscapable of form- I "ing a dyestu'ffonly under the action of light andthe other of which is capable of retaining its. capacity to form adyestufll' only in the dark, and thereupon exposing the material to theaction of light, modulated by a pat- '35 .tern as set forth.

2. A process for producing a coloured pat tern on a dark ground onwoven, knitted and plaited fabrics, leather and other materials,consisting in treatin the material with 40 two compounds, one of wiichiscapable of forming a dyestuff only under the action of light and theother of which is capable of retalning its capacity to form-a dyestuflonly 5 in the dark,': printing on the material thus" '4! treated anegative in the form of a light-absorbing covering colour which does notdye the material and thereupon exposing the material to the action oflight, modulated by a pattern as and for the purpose set, forth.

. In testimony whereof Ihave signed my name to this specification.

" WALTER HAENDEL.

